VICTORVILLE, Calif. (WHTM) — On Oct. 14, 1947, 75 years ago, Air Force test pilot Charles E. Yeager climbed into a Bell X-1 rocket plane and became the first human being to break the sound barrier in level flight.

And he did it with two broken ribs.

Charles E. (Chuck) Yeager (1923-2020) joined the U.S. Army Air Force in 1941 at the age of 18. He worked his way up the ranks, starting as an aircraft mechanic, then becoming a pilot and fighting in World War II.

After the war he became a test pilot, and was selected as part of the team of pilots working on breaking the sound barrier.

The sound barrier was already being broken. Bullets and artillery shells routinely travel faster than sound, and the “crack!” of a bullwhip is the tip breaking the sound barrier.

But a human being in an airplane is another matter. As planes accelerated to sound speed, aerodynamic drag and turbulence would cause shaking and problems with control surfaces –ailerons, flaps, and the like. There were reports of fighter craft exceeding the sound barrier in World War II, but only while diving, and these reports usually ended with the ground littered with burning wreckage.

Part of the problem was that propellors added to the turbulence. But with the coming of jet and rocket-propelled aircraft, could the sound barrier finally be broken? More importantly, could it be broken by level, controlled flights?

The Air Force had an experimental aircraft for the tests — the Bell X-1. It was called a “bullet with wings”; in fact, its shape resembled a Browning .50-caliber machine gun bullet. It was powered by a rocket engine with four chambers, each of which could be turned on and off individually. To save fuel, the plane was drop launched from a B-29 bomber. Yeager named his X-1 Glamorous Glennis after his wife.

Tests of the X-1 began in 1946, with incremental increases in airspeed, followed by adjustments and tweaks to the aircraft as needed. (Along the way the Army Air Force became the Air Force.) In October of 1947, everything was ready for the big test. But two days before the flight, Chuck and Glennis Yeager went horseback riding. Chuck was thrown from his horse and broke two ribs.

Knowing he’d be down-checked from the flight if word got out, Yeager went off base to get his ribs taped up by a civilian doctor. On the day of the test, he was still hurting — so much so he couldn’t close the hatch of the X-1. Friend and fellow pilot Jack Ridley, who was in the know, rigged up a lever with the end of a broom handle, which allowed Yeager to get the hatch shut.

From that point on, things went like clockwork. On Oct. 14, 1947, over the Mohave Desert, the B-29 dropped Glamorous Glennis from its bomb bay at 25,000 feet, the rocket ignited, and at a height of 45,000 feet, Chuck Yeager reached the speed of sound, Mach 1 (about 760 miles per hour), then surpassed it to reach Mach 1.07, about 821 miles per hour. The town of Victorville, California, became the first place in the world to hear a sonic boom. After the rocket cut off, he glided the plane to a landing.

Because of the secrecy surrounding the project, the world didn’t know about Yeager’s achievement until June 1948. Glamorous Glennis is now on display at the Smithsonian Air and Space Museum.

Chuck Yeager stayed in the Air Force until he retired in 1975. By then he’d flown 10,131.6 hours in some 361 different types and models of military aircraft.